Paper machinery



March 13, 1934. c. R. CRAWFORD PAPER MACHINERY Filed Sept. 8, 1931 Patented Mar. 13, 1 934 l T I UNITED STATES PATENT OFFICE PAPER. MACHINERY Cliff R. Crawford, Middletown, Ohio, assignor to The Black Clawson Company, Hamilton, Ohio, a corporation of Ohio Application September 8, 1931, Serial No. 561,584

6 Claims. (Cl. 92-22) This invention relates generally to engines for adjacent the upwardly moving side of the roll, 10., beating up pulping stock for use in the manufac- The beater roll has blades or knives projecting ture of paper, boxboard and like products and from its surface and by its motion causes a-flow more particularly to apparatus of the character or circulation of the water and stock in the tank commonly termed beating or breaking engines which moves over the perforated backfall memembodying or employing a perforated backfall her, the pulp or stock in required size falling or member for separating and withdrawing the stock being forced by centrifugal action through the as soon as it has been reduced to pulp or .to a perforations into a receptacle or portion of the required size. tank from which it can be carried by suitable In such engines now commonly in use, this means to the stuff chest or other paper. machines perforated backfall member consists of one heavy for further treatment. In the drawing, the backand solid piece of metal, perforated so as to penjnit fall member comprises the body portion, 13, prefthe flow of the reduced stock, this member being erably having a recess therein as indicated at 14, rigidly fixed or mounted to the foundation and into which is fitted a removable surface plate, 15, other parts of the apparatus. On account of the the whole member being of a concave shape excessive wear on the operative face or surface mounted so as to extend upwardly and adjacent of this backfall member due to friction and other to the outer surface of the roll or drum with suitcauses in the operations of a beating engine as able clearance space between and with the outer described, replacement is frequently necessary, end of the backfall member even with, above or such replacements requiring great expenditure of below the horizontal center line of said roll from time and money. Likewise this replacement carwhere it follows downwardly at a decreasing ries with it the necessity of removing the entire distance to the bottom of the tank, 11, of the backfall member and installation of a completely "apparatus. The body portion of the backfall new one. This replacement of a new backfall member is securely fastened or mounted to the member is Very troublesome as y are of a ge foundation and bottom of the tank by means of size and difficult to be made to fit accurately with anchor bolts, 17, or other suitable means. the f undati n n a unt of Wa p or t r The backfall member, 12, instead of being of causes. Imperfect fit or misalignment of bolt convenient unitary construction is so arranged connections, et f course e ult in great loss of as to permit the curved part that cooperates with time. the beater roll to be readily replaced when worn 30 On f h P cipal objects of this invention as shown. The removable surface plate is prefis therefore to provide apparatus of this character erably fitted into the recess, 15, of the body porthat is of simple construction, eflicient in opertion and made fast by screws, 18, or equivalent ation and in which-the parts subject to wear and means. These screws go through suitably located near may b as ly, economically a d qui kly r passages, 19, in the body portion, 13, and serve 35 placed. to prevent the removable surface plate from slid- Othel Objects and dvantages of my invention ing or moving out of its normal position which will e ppar t from th following d s iption, may be recessed in the body portion so that its the pp claims and the p ying drawupper surface is flush with the upper surface of i ing, in which: the body portion though the surface plate may b5 4 Fi u 1 is a longitudinal v rti al s tion of a be bolted on top of the body member without the p of a ea in engine ying this invenrecess. Preferably both the body portion and tion; the removable surface plate are perforated, these Figure 2 is a cross sectiondetail showing means perforations being so located that the holes in of attac i g a d holding the removable Surface the surface platewhich are preferably rather 45 plate of the backfall member; a d small register with the larger and similarly ar- Figure 3 is a fragmentary View Of the Ovranged holes in the body portion when the surface able plate looking in the direction of the arrow plate is in operative position. Both the body por- 3 of Fig. 1. tion, 13, and the removable plate, 15, are pref- AS illustrating a p erred embodiment of the -erably of rolled steel, the plate, 15, being rather invention, there is disclosed in the drawing the thin as compared with the heavy and rigid body outline of the roll or drum, 10, of abeating engine portion, 13, on which it is supported in surface of the ordinary or conventional construction rocontact therewith throughout substantially the tatably mounted in the tank, 11, on the apparatus entire area of the surface plate, though the body I with a perforated backfall member, 12, provided portion may be constructed of welded rolled steel. 11,0

In practice the backfall member wears out making replacement necessary. To accomplish such replacement in accordance with the present invention it is only necessary to remove the screws, 18, and withdraw the worn out or damaged plate from the body portion and replace it with a new one. The heavy body portion may be permanently secured to its mountings to prevent or check vibrations, as the replacement of a removable surface plate can be effected without in any way disturbing the mountings of the heavy body portion. Removable surface plates are made in replaceable units so that an additional or auxiliary plate may be readily kept on hand or in stock for replacement purposes. Thus when that portion of the backfall member that is. subject to constant wear becomes unserviceable it can be removed and a new surface plate very quickly installed in position requiring only a minimum of shut down time, and a minimum of labor and expense. This attachment of a new surface plate can be very quickly accomplished as such a plate is comparatively light and thin and much smaller in size than the entire backfall, so any errors in attachment hole arrangement, and any irregularities of form due to warping or other causes are of practically no consequence, although such errors or irregularities in a large and heavy unitary backfall member of prior constructions would be a vey serious matter.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus and that changes may be made therein without departing from the scope of the invention which is described in the appended claims.

What I claim is:

1. In a beater engine, a perforated backfall member of the character described, comprising a curved body portion having spaced holes therein, a separate surface plate portion supported thereupon and having holes the spacing of which corresponds to the hole spacing of the body portion, said plate portion being removable by movement in an upward direction from said body portion while the body portion is in place, and means detachably connecting the said plate portion upon said body portion.

2. A perforated backfall member of the character described, comprising a recessed body portion and a separate surface plate portion supported thereupon and removable upwardly therefrom while the body portion is inplace, said plate portion having inter-locking or surface engagement with the recess of the body portion, and a detachable connection for said plate and body portions.

3. In a beater engine, a perforated backfall member of the character described, comprising a heavy metal body portion and a separate readily removable relatively light metal surface plate portion having inter-locking engagement with said body portion and means detachably connecting said plate portion to said body portion.

4. In a heater engine, aperforated backfall member of the character described, comprising a permanently positioned body-portion, a readily removable surface plate portion having cooperating inter-fitting and inter-locking means wherebysaid portions may be assembled in operative position with the upper surface of the plate portion flush with the upper surface of the body portion and means for detachably connecting said portions in said operative positions.

5. A perforated backfall member of thecharacter described comprising a rigid body portion having positioning means at its edges and having a curved side defined by a continuous but recessed limiting portion and a central portion depressed below the upper surface of the limiting portion and provided with rows of holes, and a separate readily detachable plate portion fitting within the recess of and resting on the upper surface of said central portion and flush with the upper surface of the limiting portion, said plate portion having rows of hole spaced in accordance with the spacing of the holes in the body portion and means detachably connecting the plate portion to the body portion.

6. A beater engine backfall of the character described adapted for cooperation with a beater roll comprising a permanently positioned relatively heavy body portion the central part of which is' perforate, and a relatively light surface plate portion having spaced holes throughout sub- 

